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Biomedical subjects

S E Newton

Publications and source records attributed to S E Newton.

At least 19 recordsLinked to original sources
PubMed2005

Jordanian married Muslim women's intentions to use oral contraceptives.

BACKGROUND: High fertility rates and moderate to low contraceptive use in the Arab Islamic countries, and Jordan in particular, are issues of international nursing importance. AIM: By using the Theory of Planned Behaviour (TPB) as the conceptual framework, the relationships between married Jordanian Muslim women's previous contraceptive use, type of experience, and intention to use oral contraceptives (OCs) were examined. The relationship between selected demographic variables and intention to use OCs was also examined. METHODS: The study was part of a large cross-sectional survey. The Intention to Use Oral Contraceptive Tool was used to elicit participants' intentions and beliefs regarding oral contraceptive use. SAMPLE: The study sample was composed of 245 Jordanian married Muslim women. RESULTS: Results revealed a significant relationship between previous oral contraceptive use and intention to use OCs. The relationships between type of experience, whether successful or unsuccessful, with previous OC use, and intention to use OCs were not significant. CONCLUSION: Nursing implications regarding the provision of family planning services that are sensitive to Jordanian Muslim women's religious preferences are discussed.

Adolescent↗
PubMed2004

In vivo electroporation improves immune responses to DNA vaccination in sheep.

In vivo electroporation was utilised to enhance plasmid DNA expression in sheep muscle to improve the immune response to DNA vaccination. DNA encoding enhanced green fluorescence protein expressed at higher levels in sheep muscle following in vivo electroporation which caused minimal muscle damage. Groups of seven sheep were then given three intramuscular injections of plasmids encoding two Haemonchus contortus Ag, with and without electroporation at 0, 3 and 7 weeks. Humoral responses were enhanced in electroporated sheep. Four weeks after vaccination, all groups were injected subcutaneously with recombinant Ag formulated in Quil A. Induction of vaccine-specific immune memory was demonstrated in DNA-vaccinated sheep.

Animals↗
PubMed2003

Progress and new technologies for developing vaccines against gastrointestinal nematode parasites of sheep.

Despite the identification of highly effective native antigens for vaccination against Haemonchus contortus, particularly 'hidden' antigens derived from the intestine of adult worms, to date similar efficacy has not been shown with recombinant antigens. In addition, progress towards identification of protective antigens from other sheep gastrointestinal (GI) nematode species is limited. Coupled with this is an incomplete understanding of the mechanism of natural immunity to GI nematodes, making selection of appropriate immunization strategies and adjuvants for evaluation of candidate 'natural' antigens problematic. The current explosion in new high-throughput technologies, arising from human studies, for analysis of the genome, transcriptome, proteome and glycome offers the opportunity to gain a better understanding of the molecular pathways underlying pathogen biology, the host immune system and the host-pathogen interaction. An overview is provided on how these technologies can be applied to parasite research and how they may aid in overcoming some of the current problems in development of commercial vaccines against GI nematode parasites.

Animals↗
PubMed2002

A male-specific (cysteine-rich) protein of Oesophagostomum dentatum (Strongylida) with structural characteristics of a serine protease inhibitor containing two trypsin inhibitor-like domains.

A cDNA was isolated from an adult male Oesophagostomum dentatum gene library by screening with a male-specific, partial expressed sequence tag (EST) probe identified previously using a differential display technique. The full-length cDNA of 642 bp included 5' and 3' untranslated regions of 44 and 121 nucleotides, respectively, and encoded a predicted protein with a putative 18 amino acid signal sequence and a mature polypeptide of 14.7 kDa comprising approximately 15% cysteine residues. The amino acid sequence showed similarity with a number of proteins from Caenorhabditis elegans, parasitic nematodes, insects and amphibia, all of which contain a trypsin inhibitor-like cysteine-rich domain. A 3-dimensional structure model constructed for the O. dentatum protein (designated OdmCRP) inferred that it is composed of 2 domains, each with 5 disulfide bonds, which are indicative of the Ascaris family of serine protease inhibitors. These findings indicate that OdmCRP, with 2 structural domains relating to functionally active sites, is a new member of this inhibitor family.

Amino Acid Sequence↗
PubMed2001

A single-chain variable region immunoglobulin library from the abomasal lymph node of sheep infected with the gastrointestinal nematode parasite Haemonchus contortus.

Sheep immunoglobulin (Ig) heavy-chain (V(H)DJ(H)) and lambda light-chain variable region (V(lambda)J(lambda)) nucleotide coding sequence was isolated by reverse transcriptase-polymerase chain reaction (RT-PCR) from abomasal lymph node (ALN) B cells of immune sheep challenged with the gastrointestinal nematode parasite Haemonchus contortus. Single-chain antibodies (scFv) were then constructed with the purified V(H)DJ(H) and V(lambda)J(lambda) Ig gene region DNA using oligonucleotides to PCR and join the variable regions to a central [Gly(4)Ser](3)-linker. In a similar fashion 5'-SfiI and 3'-NotI restriction endonuclease sites were added for cloning into a phagemid expression vector. Expression of sheep scFv from pHFA phagemid in an amber-suppresser strain of Escherichia coli, after infection with filamentous phage, resulted in 10(9) sheep scFv antibodies displayed as a library on phagemid particles. Western blot analysis demonstrated sheep scFv gene expression in E. coli cell lysate and on purified library phage. In addition, four rounds of scFv-library selection against H. contortus surface antigen resulted in a 300-fold increase in the elution titre of phage recovered from parasite surface antigen. Nearly 1000 of the selected and eluted scFvs were expressed in an attempt to identify monoclonal sheep scFv against parasite antigen. Only low affinity clones were isolated during screening of this sheep scFv-library, suggesting different strategies will be needed for isolation of specific high affinity recombinant antibody in future studies.

Amino Acid Sequence↗
PubMed2001

Analysis of developmentally regulated genes of the parasite Haemonchus contortus.

Differential regulation of gene expression in the development of Haemonchus contortus was analysed using RNA arbitrarily-primed PCR. A study of third-stage larval and adult H. contortus revealed large differences between the two stages; 32 and 30% unique third-stage larval and adult RNA arbitrarily-primed PCR products, respectively. This finding is consistent with a high degree of differential gene expression between these developmental stages. A number of adult products were sequenced, revealing 11 molecules to be similar to deposits within sequence databases. Four other molecules that did not have significant similarity to sequences in the databases may represent developmentally regulated genes specific to H. contortus. Northern analysis of the putative adult-expressed molecules with homologues in the databases confirmed that four were expressed only in adults, while four were expressed in both stages, but had different sized transcripts. This may reflect differential splicing, or expression of closely related but different molecules at different life cycle stages. Two molecules were present in mRNA populations from both stages, suggesting these were false stage-associated molecules. No transcript was detected for one molecule by Northern analysis, probably due to low level of expression. In situ hybridisation analysis was used to localise expression of transcripts in the adult parasite, in particular, to gain some insight into the nature of those molecules with no known predicted function.

Amino Acid Sequence↗
PubMed2001

Molecular aspects of sexual development and reproduction in nematodes and schistosomes.

In contrast to the free-living nematode Caenorhabditis elegans, surprisingly little is known about the molecular aspects of reproduction in parasitic helminths. Investigations into such aspects would provide an improved understanding of the fundamentals of sexual differentiation, development, maturation and behaviour, as well as sex-specific genes and their expression. Such knowledge could lead to new means of parasite control by interfering with or disrupting one or more of these processes, which is particularly important given the emerging problems with genetic resistance in parasitic nematodes against anthelmintic drugs. This chapter brings together some relevant information on the sexual biology of C. elegans, summarizes studies of gender-specific expression in selected parasitic helminths of socio-economic significance, describes advanced molecular techniques for the analysis of gender-specific genes, and indicates the prospects for genomic research on reproductive processes and the implications thereof for controlling parasitic helminths.

Amino Acid Sequence↗
PubMed2000

Genomic and genetic research on bursate nematodes: significance, implications and prospects.

Molecular genetic research on parasitic nematodes (order Strongylida) is of major significance for many fundamental and applied areas of medical and veterinary parasitology. The advent of gene technology has led to some progress for this group of nematodes, particularly in studying parasite systematics, drug resistance and population genetics, and in the development of diagnostic assays and the characterisation of potential vaccine and drug targets. This paper gives an account of the molecular biology and genetics of strongylid nematodes, mainly of veterinary socio-economic importance, indicates the implications of such research and gives a perspective on genome research for this important parasite group, in light of recent technological advances and knowledge of the genomes of other metazoan organisms.

Animals↗
PubMed2000

Isolation and characterisation of sex-specific transcripts from Oesophagostomum dentatum by RNA arbitrarily-primed PCR.

In light of the lack of molecular data on the sexual differentiation, maturation and interaction of parasitic nematodes of livestock, the present study investigated sex-specific gene expression in the nodule worm, Oesophagostomum dentatum (Strongylida). Using the technique of RNA arbitrarily-primed polymerase chain reaction (RAP-PCR), 31 expressed sequence tags (ESTs) differentially-displayed between the sexes were cloned. Northern blot analysis proved ten ESTs to be expressed exclusively in males (adults and fourth-stage larvae), while two were expressed solely in female stages. None of the ESTs were expressed in infective third-stage larvae. Sequence analysis and subsequent database searches revealed two male-specific ESTs to have significant similarity to Caenorhabditis elegans (predicted) proteins, a protein containing an EGF-like cysteine motif and a serine/threonine phosphatase. Another two male-specific ESTs had similarity to non-nematode sequences. The two female-specific ESTs had similarity to vitellogenin-5 and endonuclease III (predicted) from C. elegans. The remaining ESTs had no similarity to any nucleic acid or protein sequences contained in the databases. The isolation and characterisation of sex-specific ESTs from O. dentatum provides a unique opportunity for studying the reproductive biology of parasitic nematodes at the molecular level, with a view toward novel approaches for parasite control.

Animals↗
PubMed1999

The organization of a galectin gene from Teladorsagia circumcincta.

Galectins are a family of soluble beta-galactoside-binding lectins that are conserved amongst a broad range of organisms. We have previously isolated cDNA clones coding for galectins from the sheep gastrointestinal nematode parasites Teladorsagia circumcincta, Haemonchus contortus and Trichostrongylus colubriformis, revealing a high level of identity between these molecules. This subsequent study reports the organization of the T. circumcincta Tci-gal-1 galectin gene. The coding region is broken into eight exons covering 6.6 kbp, with introns ranging in size from 55 base pairs (bp) to 2.8 kbp. Comparisons with recently reported galectin structures from Caenorhabditis elegans reveal strong architectural similarity between galectins from the parasitic and free-living nematodes, but this structure is not conserved in mammalian galectins.

Animals↗
PubMed1999

Recombinant expression of a galectin from the sheep gastrointestinal parasite Teladorsagia circumcincta: its use in isolating galectin-glycoconjugates.

Galectins, or beta-galactoside-binding lectins, are a family of proteins that have been described in vertebrates and, more recently, invertebrates, including nematode parasites. A tandem repeat-type galectin from the sheep gastrointestinal parasite, Teladorsagia circumcincta, has previously been isolated and the cDNA cloned. This molecule and each of its domains were expressed as fusion proteins with glutathione S-transferase (GST). The full-length molecule and the C-terminal domain were expressed in soluble form and the purified fusion proteins demonstrated a capacity to bind beta-galactoside sugars, with the greatest preference for lactose. The full-length fusion protein was used to successfully isolate potential galectin-glycoconjugates from within the parasite and from sheep serum.

Amino Acid Sequence↗
PubMed1999

The development of vaccines against gastrointestinal nematode parasites, particularly Haemonchus contortus.

Many parasitic nematodes are developing resistance to chemical treatment, and the search is on to produce commercially viable molecular vaccines. Much progress has been made with highly protective 'hidden antigens', especially for Haemonchus contortus, and recent work with new 'natural antigens' has yielded promising results. Here, Sue Newton and Ed Munn review the most recent advances in these two main approaches to this problem.

Animals↗
PubMed1999

Relationship of hardiness and sense of coherence to post-liver transplant return to work.

The article reports a retrospective survey designed to determine the relationship of hardiness and sense of coherence to post-liver transplant return to work (RTW). Instruments used included Pollock's Health-Related Hardiness Scale and Antonovsky's Sense of Coherence Questionnaire. Study results were based on 230 adult liver transplant recipients responding to a mailed questionnaire. After transplantation, 63% of the participants were working. Participants with higher levels of hardiness and higher sense of coherence scores demonstrated higher RTW rates. Using logistic regression, a model comprising hardiness and sense of coherence correctly classified 90% of the participants who returned to work.

Adaptation, Psychological↗
PubMed1999

Promoting adherence to transplant medication regimens: a review of behavioral analysis.

Failure to adhere to complex behavioral regimens has been a significant and long-standing problem in healthcare. Transplant recipients are one patient population that needs to learn and incorporate a multidimensional regimen of behaviors into their lives. The literature indicates that not all transplant recipients adhere to their medication regimens, which can lead to graft loss and possibly death. Behavioral analysis is often used to increase adherence to health-related regimens and has been effective for a variety of health conditions. The use of behavioral analysis as a strategy to promote adherence behaviors has not been reported in the transplant literature. Transplant coordinators and clinicians should learn the principles of behavioral analysis and apply them to the care of transplant recipients to facilitate recipients' lifelong adherence behaviors.

Health Behavior↗
PubMed1999

Renal transplant recipients' and their physicians' expectations regarding return to work posttransplant.

The purpose of the study was to explore the return to work (RTW) expectations of adult renal transplant recipients and their transplant physicians. The design was a prospective survey. Data was collected from 25 adult end stage renal disease (ESRD) patients who were admitted to a large Midwestern transplant center for renal transplantation and the surgeons who performed their transplant operations. Self-administered questionnaires were completed pretransplant by the recipients and surgeons, and at 6 weeks posttransplant by the recipients. Recipients who were employed pretransplant and were more likely to expect to RTW posttransplant, did so at higher rates than recipients who were not employed pretransplant and had physicians who did not expect them to RTW. The results illustrate that posttransplant RTW expectations of both renal transplant recipients and their physicians, when assessed pretransplant, are often congruent and are indicative of recipient posttransplant vocational rehabilitation.

Adult↗